The purpose of this lab was to find the specific heat of a given metal in order to determine the identity of the metal.
Background: This lab requires us to heat a given metal, place in a calorimeter with water , and calculate the change in the temperature. Many things need to be measured in order to ensure more accurate results. The mass of the water and metal are necessary as is the water temperature in the calorimeter before and after the metal is placed in it. After gathering this information we will calculate the specific heat. In order to calculate specific heat obviously the formula is necessary as well as an understanding of the symbols used. q=heat m=mass ΔT=change in temp and c=specific heat. Because our data does not cover the heat a formula is needed (Calculate for water). Heat is equal to mass multiplied by specific heat times temperature gained.
Or qw=mwcwΔTw Next, we can replace the variables in the specific heat equation so we can identify our metal. The formula is heat divided by mass times temperature gained equals specific heat. Or
cm=qm/mmΔTm. Once specific heat is determine all that is needed is the list of metals and their specific heats. The specific heats are:
Water- 4.184J/g*°C
Al- 0.897J/g*°C
Brass- 0.385J/g*°C
Cu- 0.385J/g*°C
Lead- 0.129J/g*°C
Stainless Steel 0.490J/g*°C
Zn- 0.390J/g*°C
Procedure:
1. Get a calorimeter (styrofoam cup) weigh and record its mass. Fill the calorimeter with enough water to submerge the metal. Reweigh and record the mass. Find the temperature of this water before placing the heated metal in it which will be done in step 3.
2. Measure the mass of the metal. Fill a beaker with enough water to cover the metal (we used about 80 millimeters). Place metal in beaker and give a minute or two for the metal and water to reach the same temperature. Turn on hot plate and place beaker there until the water begins to boil.
3. Take off hot plate and quickly and carefully use metal tongs to remove the metal from the beaker into the calorimeter. Use a second styrofoam cup as a cover, one with a hole in the top. Measure the highest temperature reached by the water in the styrofoam cup. Turn hot plate off. Put materials away safely, keeping in mind that the beaker, the water and the hot plate may still retain some heat.
REPEAT SEVERAL TIMES
Data: In order to thoroughly verify which metal was ours we ran the test 3 separate times
Calculations
Test #1
q=76.69 x 4.184 J/q degrees C x 2.1 degrees C
q=673.829J
673.829 J / 68.019g x 27.8 Degrees C
673.829 J / 1890.928 g x Degrees C
=0.356 J/ g * degrees C
Test #2
q=77.537 x 4.184 J/q degrees C x 1.0 degrees C
q= 324.415 J
324.415 J / 68.019g x 18.8 degrees C
324.415 J / 1278.7572 g * degrees C
=0.253 J/ g * degrees C
Test #3
q=84.453 x 4.184 J/q degrees C x 0.5 degrees C
q=176.676 J
176.676 J / 68.206 x 25.4 degrees C
176.676 J / 1732.4324
=0.101 g * degrees C
Data Analysis/Conclusion: Clearly we had some conflicting data results. If I had the opportunity to do this lab again I would run the test 4 or 5 times and be very meticulous. When it comes to close decimals it is fundamental that the data is precise because the little numbers make all the difference. When I did the first test and ran it through I thought I had done a step wrong by measuring the highest temperature reached with the metal in the calorimeter so I put the metal in and waited 2 minutes before measuring the temperature, thinking it would give the metal time to lose heat enough heat and the water to gain it. Obviously the lost heat explains our strange data results. Because our first result was closest to brass and copper (both specific heats are 0.385J/g*°C and our result was 0.356J/g*°C)
either could be our metal. Yet, based solely on physical properties I would say it was most likely brass. Unfortunately, due to human error the best we could do to establish our metal was based on 1 test and science requires multiple trials and even then an answer is not definitive.
Sample #6
The purpose of this lab was to find the specific heat of a given metal in order to determine the identity of the metal.
Background: This lab requires us to heat a given metal, place in a calorimeter with water , and calculate the change in the temperature. Many things need to be measured in order to ensure more accurate results. The mass of the water and metal are necessary as is the water temperature in the calorimeter before and after the metal is placed in it. After gathering this information we will calculate the specific heat.
In order to calculate specific heat obviously the formula is necessary as well as an understanding of the symbols used. q=heat m=mass
ΔT=change in temp and c=specific heat. Because our data does not cover the heat a formula is needed (Calculate for water). Heat is equal to mass multiplied by specific heat times temperature gained.
Or qw=mwcwΔTw
Next, we can replace the variables in the specific heat equation so we can identify our metal. The formula is heat divided by mass times temperature gained equals specific heat. Or
cm=qm/mmΔTm.
Once specific heat is determine all that is needed is the list of metals and their specific heats.
The specific heats are:
Procedure:
1. Get a calorimeter (styrofoam cup) weigh and record its mass. Fill the calorimeter with enough water to submerge the metal. Reweigh and record the mass. Find the temperature of this water before placing the heated metal in it which will be done in step 3.
2. Measure the mass of the metal. Fill a beaker with enough water to cover the metal (we used about 80 millimeters). Place metal in beaker and give a minute or two for the metal and water to reach the same temperature. Turn on hot plate and place beaker there until the water begins to boil.
3. Take off hot plate and quickly and carefully use metal tongs to remove the metal from the beaker into the calorimeter. Use a second styrofoam cup as a cover, one with a hole in the top. Measure the highest temperature reached by the water in the styrofoam cup. Turn hot plate off. Put materials away safely, keeping in mind that the beaker, the water and the hot plate may still retain some heat.
REPEAT SEVERAL TIMES
Data: In order to thoroughly verify which metal was ours we ran the test 3 separate times
Calculations
Test #1
q=76.69 x 4.184 J/q degrees C x 2.1 degrees C
q=673.829J
673.829 J / 68.019g x 27.8 Degrees C
673.829 J / 1890.928 g x Degrees C
=0.356 J/ g * degrees C
Test #2
q=77.537 x 4.184 J/q degrees C x 1.0 degrees C
q= 324.415 J
324.415 J / 68.019g x 18.8 degrees C
324.415 J / 1278.7572 g * degrees C
=0.253 J/ g * degrees C
Test #3
q=84.453 x 4.184 J/q degrees C x 0.5 degrees C
q=176.676 J
176.676 J / 68.206 x 25.4 degrees C
176.676 J / 1732.4324
=0.101 g * degrees C
Data Analysis/Conclusion: Clearly we had some conflicting data results. If I had the opportunity to do this lab again I would run the test 4 or 5 times and be very meticulous. When it comes to close decimals it is fundamental that the data is precise because the little numbers make all the difference. When I did the first test and ran it through I thought I had done a step wrong by measuring the highest temperature reached with the metal in the calorimeter so I put the metal in and waited 2 minutes before measuring the temperature, thinking it would give the metal time to lose heat enough heat and the water to gain it. Obviously the lost heat explains our strange data results. Because our first result was closest to brass and copper (both specific heats are 0.385J/g*°C and our result was 0.356J/g*°C)
either could be our metal. Yet, based solely on physical properties I would say it was most likely brass. Unfortunately, due to human error the best we could do to establish our metal was based on 1 test and science requires multiple trials and even then an answer is not definitive.